Recently, as an exterior material for electric/electronic products, office products, and the like, thermoplastic resins having lower specific gravity than glass or metal and excellent formability are widely used. Thus, in the field of thermoplastic resins, functions and appearances as exterior materials are growing in importance, and importance of impact resistance and scratch resistance is strengthened, which represent characteristics capable of withstanding external shock or scratch. Moreover, with the development of high-grade electric/electronic products, aesthetics of the products is increasingly important, which leads to increased interest in transparent thermoplastic resins having excellent scratch resistance.
Polycarbonate resins are a representative thermoplastic resin that have a heat deflection temperature of 135° C. or higher, and exhibit excellent properties in terms of transparency, impact resistance, self-extinguishing properties, dimensional stability and heat resistance, and are widely used in various applications, such as exterior materials of electronic and electric products, office equipment, automobile components, and the like.
However, polycarbonate resins and resin compositions have a limitation in use as exterior materials or optical films for laptops, mobile phones, and the like due to poor scratch resistance. A polycarbonate film can be coated with a scratch-resistant film in order to improve scratch resistance of polycarbonate resins. In this case, an expensive scratch-resistant film and an additional coating process can cause an increase in manufacturing costs.
Therefore, besides such a film coating technique, various studies on various methods have been made to improve scratch resistance of polycarbonate resins and resin compositions. Thereamong, blending polycarbonate resins with a scratch-resistant resin such as acrylic resins is most commonly used.
However, when polycarbonate resins are blended with acrylic resins to improve scratch resistance, impact resistance and heat resistance of the polycarbonate resins can be drastically reduced, and compatibility between the blended resins can considerably increase haze, thereby damaging transparency, which is one of the advantages of the polycarbonate resins.
Therefore, there is a need for a polycarbonate resin composition having excellent scratch resistance without deterioration in inherent physical properties, such as impact resistance, heat resistance, and transparency.